Natural gas pipelines stretch for thousands of miles across entire continents and inspecting them for potentially dangerous leaks is a full-time, never-ending job. To take some of the pressure off, NASA is testing a quadcopter equipped with a miniature methane gas sensor originally designed for testing the Martian atmosphere. The space agency says that the exceptional sensitivity of the equipment makes it possible to monitor many miles of pipeline at a time from the air.

Methane leaks are not only a safety and environmental hazard, but even small, harmless leaks can add up to a major loss of revenue over time. To prevent this from happening, the gas industry employs a small army of inspectors who traverse the length of the pipeline with sniffers to seek out even the smallest leaks. It's slow, tedious, and sometimes dangerous work, which would be greatly sped up if it could be managed by autonomous UAVs flying overhead.

A key factor in achieving this is developing sensors that are sensitive enough to detect small leaks at a distance. Developed by NASA's Jet Propulsion Laboratory (JPL) in California for use on Mars, the Open Path Laser Spectrometer (OPLS) is rated at being able to detect methane in parts per billion by volume, and is small enough to be installed in a quadcopter.

The system is currently undergoing flight tests in a joint venture with the Pipeline Research Council International (PRCI), which is funding the project. In February, scientists and engineers from JPL and the Mechatronics, Embedded Systems and Automation (MESA) Lab at the University of California, Merced carried out a series of tests in central California at the Merced Vernal Pools and Grassland Reserve.

The tests were the latest in a series conducted since 2014 using various platforms. For this round, the OPLS was flown at different distances from a controlled methane source to test the accuracy and robustness of the system.

NASA sees the quadcopter, with its ability to fly and hover vertically, as a major advantage for hunting down leaks. However, the project will also carry out flight tests of fixed-wing drones, which can fly faster and farther than the copter and may be more practical in more remote settings.

"These tests mark the latest chapter in the development of what we believe will eventually be a universal methane monitoring system for detecting fugitive natural-gas emissions and contributing to studies of climate change," says Lance Christensen, OPLS principal investigator at JPL.